Doors are means for controlling entry. Whether one desires to keep out insects or to keep out burglars, doors are designed with the object of providing one with means for selectively controlling passage through one's portals.
Throughout the ages a multitude of devices have been designed to close doors to the unwanted. This search for security has traveled from the moats and drawbridges of the Middle Ages to the ubiquitous chain latch of modern apartments. With the recent increase in crime, most notably of burglaries, homeowners have renewed the search for a device with which to safely secure their homes from unwanted intruders. Chain latches and other edge mounted latches and bolts have proved far too susceptible to the shear forces that are generated between the door frame and the edge of the door itself when strong force is applied to the outside of the door. The failure mode for these devices is generally the uprooting of support screws or the like as a result of these shear forces.
Deadbolts and other locks mounted in the core of the door are susceptible to tampering via devices inserted into the crevice between the door and the door frame. Also, these locks require a hollow void in the core of the door which weakens the strength of the door itself. Therefore, repeated blows or kicks will often cause doors secured by such devices to splinter and fracture in the vicinity of the device.
The need has been recognized for a device which is specifically designed to resist failure from the extreme forces which may easily be generated on the outside of the door by an intruder. The mechanism of the present invention channels these factors from the door to an adjacent wall.
Woodard et al., U.S. Pat. No. 2,760,806 discloses a device for limiting, rather than preventing, opening movement of a door. While this device can be said to redirect force from outside the door to an adjacent wall, its purpose is to keep out insects, not burglars. Thus, this device permits opening of the door to an arc of ninety degrees. Further opening is only prevented so that a spring attached to the door will have enough leverage to be able to automatically swing the door closed. For this reason, the Woodard-type device is designed for use with a door which is mounted parallel to an adjacent wall. The device automatically engages the adjacent wall every time the door is swung open ninety degrees. Thus, it provides no means for completely preventing opening the door from the outside. No means for selectively engaging or disengaging the device are required or included since access to the room is always available from either side of the door. Separate means for selectively barring access to the room from the outside world would always be required in a door equipped with the Woodard-type device.